This invention relates to a method and apparatus for supplying blast to a blast furnace.
Conventionally, the use of heated blast air introduces nitrogen to the furnace, which must be removed from the blast furnace top gas if carbon capture and storage are to be used. One approach to the issue of removing nitrogen from the top gas has been described by G. Zuo and A. Hirsch, SP10-Top Gas Recycling Blast Furnace no2-3, Proceedings of 4th ULCOS Seminar, 1-2 October 2008. In this article, oxygen is used in place of preheated air and carbon monoxide rich top gas is re-injected into the blast furnace.
U.S. Pat. No. 4,877,013 describes a hot blast stove installation with a plurality of hot blast stoves alternately operating during a heating phase and a blowing phase. A heat exchanger removes heat from cold blast in the cold blast main before supplying cold blast to the stoves.
JP2012031495 describes producing hot blast from a plurality of hot blast furnaces including combustion exhaust gas recirculation.
JP S57137407 describes using a heat exchanger in a regeneration chamber of a hot blast stove.
Peter Heinrich “Heat recovery in blast furnace stove plants”, MPT-Metallurgical Plant and Technology, no.3, 1 Jan. 1982 (1982-01-01), page 10,
XP001408316 describes using heat recovery from stove waste gases in blast furnace stove plants.